Hydrocarbon fluids such as oil and natural gas are obtained from a subterranean geologic formation, referred to as a reservoir, by drilling a well that penetrates the hydrocarbon-bearing formation. Once a wellbore has been drilled, the well must be completed before hydrocarbons can be produced from the well. A completion involves the design, selection, and installation of equipment and materials in or around the wellbore for conveying, pumping, or controlling the production or injection of fluids. After the well has been completed, production of oil and gas can begin.
Sealing systems, such as packers, are commonly deployed in a well as completion equipment. Packers are often used to isolate portions of a wellbore from one another. For example, packers are used to seal the annulus between a tubing string and a wall (in the case of uncased or openhole) or casing (in the case of cased hole) of the wellbore, isolating the portion of the wellbore above the packer from the portion of the wellbore below the packer. Some packers maybe actuated by hydraulic pressure transmitted either through the tubing bore, annulus, or a control line. Other packers may be actuated via an electric line deployed from the surface of the wellbore. Furthermore, some packers have been used that employ elements that respond to the surrounding well fluids and swell to form a seal. Many different materials have been disclosed as capable of having this feature. Often swelling packers have a limited ability to create contact pressure between the tubular and wall of the wellbore. When a wellbore has non-uniformity and eccentricity, as often encountered in openhole wellbores, the swelling packer's ability to form contact pressure between a tubular and the wall of the wellbore may be further limited. The amount of contact pressure is a factor in the packer's ability to control the level of differential pressure between portions of the wellbore.
Because a swellable packer with a greater amount of contact pressure may be desirable it may be desirable to place the greatest amount of swellable material between the drain pipe/support tube and the open or cased hole. Generally, more material would translate to a greater maximum swell diameter. However, it may be necessary to provide internal support for the swellable material. Particularly, when the swellable material is internally supported it is more stable under high differential pressures. Thus, it is desirable to have a swellable packer that is sufficiently internally supported to be adequately stable under high differential pressures while also maintaining a large maximum swell diameter.